@mimmo
Reseating the sim card especially if you remove it for a good 10 minutes along with generally making sure there is nothing affecting the contact between the phone and it will "reprovision" the sim card. Whether you are getting an error message "sim not provisioned" or experiencing calling issues with incoming/outgoing, straight to voicemail or text sending/recieving or data access while some or all other services are working its an issue with the phone connecting to the network thru the sim card.
If reseating does not work suspending the phone via lost/stolen will also "reprovision" the sim by removing that form of the sim card being the vehicle to communicate with the network. It also works with the add $1 payment trick to reactivate accounts as a form of getting the sim card and the network provider to communicate with one another.
Lastly having a moderator reprovision the sim card and/or reset the account is cutting the connection of the sim card to the account thus the provider will create a new connection. When service issues continue to persist or fail that is when sim card replacement is necessary as the sim card has lost the ability to be the conduit betwen the phone and the network provider.
A new sim has to be provisioned to the account and the provider network. A card that fails to activate and deliver services while an account has been created has to be provisioned by a moderator to work. Occasionally the sim card is a dud due to inferior workmanship or materials which can also cause a failure down the road.
This is why credits are issued for sim card replacements as there is a percentage of sim cards that fall within the failure rate of production. Similar to the pill being 99% effective.....one out of every hundred women on it every month will be welcoming a little bundle of joy ( if they so choose) 9 months later. The average industry sim card failure rate is much higher at about 10% of production.
